No matter what I do, it keeps asking for my credit card information.

i was trying to download a free app (Satisdom) and it asked for my card information for the first time since I’ve had my IPhone 7. I tried to put it in, but it said something like “This credit card is already on this account”, so I deleted the card, but it’s not deleting it and just doing nothing when I press delete in my settings. I was planning on putting the card in again. If anyone could help me I would greatly appreciate it. Thanks.🙂